package com.example.springboot.common;

import cn.hutool.core.util.StrUtil;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.example.springboot.exception.ServiceException;
import com.example.springboot.mapper.UserMapper;
import com.example.springboot.entity.User;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * 功能：
 * 作者：sharon
 * 日期：2024-06-23 16:14
 **/
public class JwtInterceptor implements HandlerInterceptor{

    @Resource
    private UserMapper userMapper;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler){
        String token = request.getHeader("token");  //header里面传过来的参数
        if (StrUtil.isBlank(token)){
            token = request.getParameter("token");  // url参数 ？token=xxxx
        }
        //如果不是映射到方法直接通过
        if (handler instanceof HandlerMethod){
            AuthAccess annotation = ((HandlerMethod) handler).getMethodAnnotation(AuthAccess.class);
            if (annotation != null) {
                return true;
            }
        }
        //执行认证
        if (StrUtil.isBlank(token)) {
            throw new ServiceException("401", "请登录");
        }
        //获取token中的user id
        String userId;
        try{
            userId = JWT.decode(token).getAudience().get(0); //JWT.decode(token) 解码 jwt token
        }catch (JWTDecodeException J){
            throw new ServiceException("401", "请登录");
        }
        //根据token中的userid查询数据库
        User user = userMapper.selectById(Integer.valueOf(userId));
        if (user == null) {
            throw new ServiceException("401", "请登录");
        }
        //通过用户密码加密后生成一个验证器验证token
        JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256(user.getPassword())).build();
        try {
            jwtVerifier.verify(token); //验证token
        } catch (JWTVerificationException e) {
            throw new ServiceException("401", "请登录");
        }
        return true;
    }
}
